Been helping the BIL get his well back up and running. His tank is old, 60's probably.Has no bladder, gets waterlogged after 2-3 days, have to drain the tank down to restore air bubble. Estimate the tank at 3 ft tall and around 20 inches diameter, threaded 1 inch hole in top w/pipe plug. Could I insert something into the tank thru this hole and makeshift a bladder?
Hi, cougar14!
As evidenced by all the excellent responses to your questions provided by the esteemed and experienced Members of this fine Forum, it's clear you've come to the right place.
Their advice and opinions align closely with my travails, so please permit me to share my water well journey with you.
I purchased this house and wooded property about 30 years ago when the only available utility was electricity.
In the intervening years, natural gas, high speed internet, and a 12" water main have come to reside in my front yard (as well as several upscale suburban developments down in the valleys in front of and behind me

).
I have since availed myself of the natural gas (lower cost than electric heat and much less work than cutting, splitting, and stacking firewood) and high speed internet (good riddance to "dial-up").
I still use my water well.
It is an approx. 250' deep well located at the bottom of an old cistern with a 24" X 24" hatch.
Along with the well head, piping, and electrical service for the pump residing in the cistern, there was a galvanized pressure tank approx. 5' tall by 24" in diameter (60-70 gallons?).
The only service required was to re-pressurize the tank every 6 months or so to keep the pump from short cycling.
About 10-11 years ago, the system would not build pressure although I could hear the pump running.
I ordered a new pump and called the well company.
They pulled the 250', 1" galvanized drop and the pump to reveal one of the lowest 20' lengths of galvanized pipes had rusted through.
I had them replace the 250' of galvanized pipe with PVC along with the new pump (as long as they had it out) although the old RACO pump was still working.
I've heard RACO pumps are high quality so I retained it as a spare.
At the time, I also purchased and installed a Franklin "Pumptrol" box which electronically monitors pump operation and shuts down the pump if the well runs dry.
Everything was fine until about a year and a half ago when I lost water service.
The old galvanized pressure tank has rusted through with a small pinhole and had proceeded to fill the old cistern half way up with water!
Luckily, that Franklin "Pumptrol" protected the pump and it was still good so I went to Lowe's and bought the largest A.O. Smith bladder tank that would fit through the hatch (85 gallons), a new pressure switch, gauge, and fittings and had a "fun" time removing the old tank and installing the new (150 lb.) tank.
BTW, I got 20% off the price of the tank and parts by opening a Lowe's credit account which I promptly paid off when the bill came.
The system has worked perfectly and like others, I am more than satisfied with the care free operation.
Just in case you do not wish to go this route, my old tank had a sticker that said a "Merrill Float" ( a type of bladder for conventional, non-bladder tanks) had been installed.
When I inspected the interior of the old tank, I found no evidence of the bladder's remains.
The Merrill Company (makers and sellers of the site installed bladder) is still in business and here is a link to their website:
Air Volume Controls and Floats – Merrill Manufacturing
If it were me, I'd still go with a new bladder tank, but the option still exists for you to install a site installed bladder.
Good luck!
John